Method and apparatus of intra-inter prediction mode for video coding
Method and apparatus of video coding are disclosed. According to the method, a boundary region in the current block is determined. For each pixel in the boundary region, an Intra predictor and an Inter predictor care derived. An Intra-Inter predictor is generated by blending the Intra predictor and the Inter predictor. Pixels in the boundary region of the current block are encoded or decoded using the Intra-Inter predictor. For the remaining pixels in the current block not belonging to the boundary region, the pixels are encoded or decoded using the Inter predictor or the Intra predictor. In another method, the Intra-Inter prediction process is implemented by scaling the sum of the Intra weighting factor and the Inter weighting factor is scaled to a power-of-2 number to avoid the need for the division operation. In yet another method, the Intra-Inter prediction is applied depending on the current block size.
1. A method of video coding performed by a video encoder or a video decoder, the method comprising:
receiving input data associated with a current block in a current picture at an encoder side or receiving a video bitstream including compressed data of the current block at a decoder side:
deriving an Intra predictor from Infra reference pixels, the Intra reference pixels being in the current picture located above a top boundary of the current block or on a left side of a left boundary of the current block, and the Intra reference pixels being coded prior to the current block;
deriving an Inter predictor comprising Inter reference pixels located in a reference block in a reference picture, the reference block being coded prior to the current block:
generating a weighted sum of the Intra predictor and the Inter predictor, comprising:
multiplying the Intra predictor with an Intra weighting factor to obtain a weighted Intra predictor:
multiplying the Triter predictor with an Inter weighting factor to obtain a weighted Inter predictor; and
adding the weighted Intra predictor and the weighted Inter predictor,
wherein a sum of the Intra weighting factor and the Inter weighting factor is a power-of-2 number;
generating a normalized Intra-Inter predictor by applying a right-shift operation by a number of bit or bits to the weighted sum of the Intra predictor and the Inter predictor. the number being log-base-2 of the sum of the Intra weighting factor and the Inter weighting factor: and
encoding or decoding the current block using the normalized Intra-Inter predictor.
2. The method of claim 1 , wherein the generating a-the weighted sum of the Intra predictor and the Inter predictor further comprises
adding a bias to a result of the adding the weighted Intra predictor and the weighted Inter predictor.
3. An apparatus of video coding in a video coding system, the apparatus comprising one or more electronic devices or processors configured to:
receive input data associated with a current block in a current picture at an encoder side or receiving a video bitstream including compressed data of the current block at a decoder side;
derive an Intra predictor from Infra. reference pixels, wherein the Intra reference pixels being in the current picture located above a top boundary of the current block or on a left side of a left boundary of the current block, and the Intra reference pixel being coded prior to the current block;
derive an Inter predictor comprising Inter reference pixels located in a reference block in a reference picture, the reference block being coded prior to the current block:
generate a weighted sum of the Intra predictor and the Inter predictor by performing:
multiplying the Intra predictor with an Intra weighting factor to obtain a weighted Intra predictor:
multiplying the Inter predictor with an Inter weighting factor to obtain a weighted Inter predictor; and
adding the weighted Intra predictor and the weighted Inter predictor,
wherein a sum of the Intra weighting factor and the Inter weighting factor is scaled to a power-of-2 number;
generate a normalized Intra-Inter predictor by applying a right-shift operation by a number of bit or bits to the weighted sum of the Intra predictor and the Inter predictor, the number being log-base-2 of the sum of the Intra weighting factor and the Inter weighting factor; and
encode or decode the current block using the normalized Intra-Inter predictor.
4. A method of video coding performed by a video encoder or a video decoder, the method comprising:
receiving input data associated with a current block in a current picture at an encoder side or receiving a video bitstream including compressed data of the current block at a decoder side;
disabling an Intra-Inter prediction mode for the current block if a size of the current block meets one of conditions including (i) being greater than a maximum block size and (ii) being smaller than a minimum block size;
in a case that the Intra-Inter prediction mode is not disabled, determining whether the Intra-Inter prediction mode is selected for the current block;
when the Intra-Inter prediction mode is determined as selected for the current block:
deriving an Intra predictor from Infra reference pixels, the Intra reference pixels being in the current picture located above a top boundary of the current block or on a left side of a left boundary of the current block, and the Intra reference pixel being coded prior to the current block;
deriving an Inter predictor comprising Inter reference pixels located in a reference block in a reference picture, the reference block being coded prior to the current block:
generating an Intra-Inter predictor by blending the Intra predictor and the Inter predictor; and
encoding or decoding the current block using the Intra-Inter predictor; and
when the Intra-Inter prediction mode is determined as disabled or not selected for the current block:
deriving either the Intra predictor or the Inter predictor; and
encoding or decoding the current block using the derived Intra predictor or the derived Inter predictor.
5. An apparatus of video coding in a video coding system, the apparatus comprising one or more electronic devices or processors configured to:
receive input data associated with a current block in a current picture at an encoder side or receiving a video bitstream including compressed data of the current block at a decoder side;
disable an Intra-Inter prediction mode for the current block if a size of the current block meets one of conditions including (i) being greater than a maximum block size and (ii) being smaller than a minimum block size;
in a case that the Intra-Inter prediction mode is not disabled, determine whether the Intra-Inter prediction mode is selected for the current block:
when the Intra-Inter prediction mode is determined as selected for the current block:
derive an Intra predictor from Intra reference pixels, the Intra reference pixels being in the current picture located above a top boundary of the current block or on a left side of a left boundary of the current block, and the Intra reference pixel being coded prior to the current block;
derive an Inter predictor comprising Inter reference pixels located in a reference block in a reference picture, the reference block being coded prior to the current block;
generate an Intra-Inter predictor by blending the Intra predictor and the Inter predictor; and
encode or decode the current block using the Intra-Inter predictor; and
when the Intra-Inter prediction mode is determined as disabled or not selected for the current block:
derive either the Intra predictor or the Inter predictor; and
encode or decode the current block using the derived Intra predictor or the derived Inter predictor.
6. The method of claim 4 , wherein whether the Intra-Inter prediction mode is selected for the current block is specified by a block level flag.